* Minimal Fennel Love2D Setup

In the lead up to the semi-annual [[https://itch.io/jam/autumn-lisp-game-jam-2018][Autumn Lisp Game Jam]] I thought I'd look into Phil Hegelberg's approach to last Aprils Jam, using [[https://love2d.org/][love2d]] in concert with [[https://fennel-lang.org/][fennel]]. Phil outlines his approach on his [[https://technomancy.us/187][blog]].

This repo contains the minimal viable setup to get started with Phil Hegelberg's game design process, plus some additional libraries.

* Getting Started
The following commands will clone this project and duplicate its structure into a new folder =$PROJECT_NAME=

#+BEGIN_SRC bash
git clone https://gitlab.com/alexjgriffith/min-love2d-fennel.git 
./min-love2d-fennel/.duplicate/new-game.sh $PROJECT_NAME
#+END_SRC

Check out the makefile and conf.lua files in =$PROJECT_NAME=, updating them with information relevant to your game.

You can enter =love .= in the =$PROJECT_NAME= directory to run your game, or =make run=.

The following lines with =Update= should be changed in the =makefile= and =love.conf= to reflect your game.

#+BEGIN_SRC makefile
VERSION=0.1.0
LOVE_VERSION=11.4
NAME=change-me # Update
ITCH_ACCOUNT=change-me-too # Update
URL=https://gitlab.com/alexjgriffith/min-love2d-fennel # Update
AUTHOR="Your Name" # Update
DESCRIPTION="Minimal setup for trying out Phil Hagelberg's fennel/love game design process." # Update
#+END_SRC

#+BEGIN_SRC lua
love.conf = function(t)
   t.gammacorrect = true
   t.title, t.identity = "change-me", "Minimal" -- Update
   t.modules.joystick = false
   t.modules.physics = false
   t.window.width = 720
   t.window.height = 450
   t.window.vsync = false
   t.version = "11.4"
end
#+END_SRC

* Emacs Setup

Once you install the latest version of [[https://gitlab.com/technomancy/fennel-mode][fennel-mode]], you can run
=C-u M-x fennel-repl= followed by =love .= to launch a repl.

* Default Project Structure

The =make= process as-is will only compile the contents of the root folder and the =lib/= folder+subfolders, so make sure to put your game files in either of those. 

Specifically, every =.fnl= file needed at runtime needs to be situated in the root folder, and every file which is not a =.lua= or =.fnl= file needs to be put inside =lib/=.

In order to use macros, they have to be put in =.fnl= files inside =lib/=.

* Seperate your Code into a /src directory

  If you want a more opinionated layout, you can use pass in a =--layout= parameter when creating your project.

#+BEGIN_SRC bash
./min-love2d-fennel/.duplicate/new-game.sh $PROJECT_NAME --layout=seperate-source
#+END_SRC

This build uses =gamestate= rather than Phil's approach to scene seperation and puts all your =.fnl= files into a =/src= directory. It also provides a seperate makefile that handles this layout. 

Note, any macros will have to be placed in the root of the project or in the =lib= folder (this can be modified in =main.lua=)

Presently the only layouts are =clone= and =seperate-source=. If you want to make your own check out the =.duplicate= directory to see how they work.

* Release Process

Use =make linux=, =make windows=,  =make mac=, or =make web= to create targets for each platform, or =make release= to make all four. Check out the makefile for more commands, and remember to edit your game data in it!

* Targeting the development branch of love (12.0) - LINUX ONLY
You can target the development branch of love (version 12.0) by setting the `LOVE_VERSION` parameter in the makefile to 12.0. Note that because we are working from a github artifact, rather than a release, you will also have to pass in your github username and a github PAT.

** Getting a PAT
To download artifacts created by the Github actions CI you will need to get an access token from "settings -> developer settings -> personal access tokens". The token needs `workflow` and `actions:read` permissions.

** Creating a credentials.private file
By default the makefile looks for `credentials.private` in the root directory of the project. `*.private` is part of `.gitignore` so personal information stored here will not be part of the git history or get pushed to a remote server.

The contents should look something like this:
#+BEGIN_SRC bash
GITHUB_USERNAME=username
GITHUB_PAT=PAT
#+END_SRC

Note: this is presently linux only, however it may be expanded in the future to cover macos and windows.

* Phil's Modal Callbacks (PMC)

Phil Hegelberg's [[https://gitlab.com/technomancy/exo-encounter-667/][exo-encounter-667]] is structured using a modal callback system. Each game state has a mode and each mode has a series of specific callbacks.

If you design your game as a series of states in a very simple state machine, for example *start-screen*, *play* and *end*, with unidirectional progression, you can easily separate the logic for each state into state/mode specific callbacks. As an example, in order to have state dependant rendering that differs between start-screen,play and end you could provide a *draw* callback for each of those states. Similarly if we need state dependent logic and keyboard input we could provide *update* and *keyboard* callbacks. As you iterate you can add and remove callbacks and states/modes as needed with very little friction.
